

public class TextDemo {
    public static void func(){
        System.out.println(10);
    }
    public static void main(String[] args) {
        func();

       /* System.out.println(""+'a'+1);
        long nnum1 = 2200000000L;
*/
     /*   String str = "helloworld" ;
        System.out.println(str.replaceAll("l", "_"));
        System.out.println(str.replaceFirst("l", "_"));
*/
      /*  String str = "helloworld" ;
        System.out.println(str.substring(5));
        System.out.println(str.substring(0, 5));

        System.out.println(str);
*/

        String s1 = "nihaoya";
        String s2 = new String("nihaoya");
        String s3 = new String("nihaoya");

        if(s2==s3){
            System.out.println("s3==s2");
        }

    }
}
